. 
216 STUDY OF NATURAL HISTORY. 
arrangement. It then becomes necessary to remodel 
the whole; and if, after this, no general results can be 
obtained —if there is no regularity in the occurrence 
of the same analogous forms in the different groups 
—our circles want verification, and must of course 
be considered hypothetical. 
(152.) The presence of such remarkable forms 
as have been just instanced in a natural group, 
would seem to point out at once the most obvious 
means of deciding on the number of divisions which 
a genus contains; and as every distinct modification 
is the type of a sub-genus, we derive, in that first or 
lowest stage of induction which we are now sup- 
posing, great help in determining the number of 
divisions in a genus. It may so happen, that in one 
we reckon four, in another five, in a third seven, or 
even more. It then becomes an important question, 
whether these assumed divisions or types can be 
augmented or reduced so as to bring them to a 
definite number in each group. If this can be accom- 
plished, it is clear that another principle of harmony 
will be discovered ; and we shall have good reason to 
conclude that the number of divisions into which the 
majority of our groups can be divided, will be that 
most prevalent, if not universal, in all others. The 
verification, however, of such a theory cannot be satis- 
factorily attained until we quit genera, and ascend to 
higher generalisations; and for the following reasons. 
(153.) Suppose, for instance, we looked to the 
genus Trichius among coleopterous insects, and 
agreed with an eminent entomologist in dividing it 
into seven principal sections or sub-genera; and we 
assume these to be natural. But on turning to the 
